The present invention relates to a document conveying apparatus and, more concretely, to a document conveying apparatus of the type in which a document is inserted by hand into a document conveying passage. The invention further relates to an image-forming machine equipped with the above document conveying apparatus, such as an image-forming machine which is an electrostatic copier.
An electrostatic copier capable of copying documents of large sizes such as documents of, for example, JIS A0-size, is equipped at its upper end portion with a document conveying apparatus. The document conveying apparatus includes a document conveying passage which is so arranged as to extend nearly horizontally and a pair of rollers for introducing document which is disposed at a document insertion portion in the document conveying passage. A document table is disposed on the upstream side of the document insertion portion. On the downstream side of the pair of document introduction rollers in the document conveying passage, there are arranged a document holder roller and a pair of discharge rollers in this order from the upstream toward the downstream. The pair of document introduction rollers and the pair of discharge rollers are constituted by driven rollers and follower rollers, and the document holder roller is constituted by a follower roller. A support frame is supported at an upper end of the copier body so as to pivot on a turn shaft between an open position where the support frame permits at least part of a region of the upper surface portion of the copier body to be exposed upward and a closed position where the support frame covers the region of the upper surface portion of the copier body. The driven rollers of the pair of document introduction rollers and of the pair of discharge rollers are rotatably disposed at upper end portions of the copier body. The follower rollers of the pair of document introduction rollers and of the pair of discharge rollers as well as the document holder roller are rotatably disposed in the support frame.
The driven roller of the pair of document introduction rollers is drive-coupled to an electric motor provided in the copier body through a power transmission mechanism inclusive of an electromagnetic clutch. The driven roller of the pair of discharge rollers is drive-coupled to the above electric motor though a power transmission mechanism. The document holder roller is drive-coupled to the follower roller of the pair of discharge rollers through a pulley and a belt. A document-reading position is provided on the document conveying passage, and a glass having a horizontal upper surface is disposed at the document-reading position. The glass is disposed at an upper end of the copier body. When the support frame is brought to the closing position, the follower rollers of the pair of document introduction rollers and of the pair of discharge rollers are brought into pressed contact with the corresponding driven rollers provided in the copier body, and the document holder roller is brought into pressed contact with the upper surface of the glass. A close-contact type image sensor including a source of light is disposed under the glass in the copier body. An inserted document detector switch is disposed right on the upstream side of the pair of document introduction rollers in the document conveying passage. A trailing end detector switch is disposed right on the downstream side of the pair of document introduction rollers to detect the trailing end of the document.
The inserted document detector switch is turned on when a document is inserted by hand through the document insertion portion and its leading end is inserted in a nip portion of the pair of document introduction rollers and is positioned. After a lapse of a predetermined period of time from when the inserted document detector switch is turned on, the electromagnetic clutch is turned on and, then, the electric motor is actuated to rotatively drive the pair of document introduction rollers, the document holder roller and the pair of discharge rollers. The document is conveyed passing through the document conveying passage by the pair of document introduction rollers, the document holder roller and the pair of discharge rollers, and is discharged by the pair of discharge rollers from the document conveying passage. When the trailing end of the document passes over the trailing end detector switch and the detector switch is caused to be turned off, the electromagnetic clutch is turned off and the pair of document introduction rollers cease to rotate. After a lapse of a predetermined period of time from when the trailing end detector switch is turned off, the electric motor is brought into a halt, and the document holder roller and the pair of discharge rollers cease to rotate. The image of the document conveyed by the document conveying apparatus as described above is, then, read by the close-contact type image sensor as it passes through the image-reading position disposed on the way of the document conveying passage. The image read by the sensor is sent to the image-forming portion of the copier and is turned into a toner image. The toner image is transferred and fixed on a paper conveyed from a paper-holding portion disposed in the copier.
In order to copy the document by using the above-mentioned conventional document conveying apparatus, the user, first, inserts the document through the document insertion portion, inserts the leading end of the document by hand into a nip portion of the pair of document introduction rollers to position the document in the direction of conveyance and, further, positions the leading end of the document at right angles with the direction of conveyance to prevent the paper from being fed aslant. In practical cases, however, the leading end of the document tends to become aslant at a moment when the leading end of the document is nipped by the pair of document introduction rollers that are rotatively driven, making it difficult to reliably prevent the document from being fed aslant and, hence, causing the document to be damaged. The reason is because a gap on the upstream side of the nip portion of the pair of document introduction rollers is formed to be gradually decreases toward the nip portion between the outer peripheral surfaces of the driven rollers and the outer peripheral surfaces of the follower rollers, and it is, therefore, relatively difficult for the user to insert by hand the leading end of the document uniformly along the nip portion of the pair of document introduction rollers over the whole region in the direction of width thereof to position the document. In particular, it becomes more difficult to correctly position the document as the size of the document increases. In the image-forming machine which is equipped with the above-mentioned document conveying apparatus and which reads the image of the document conveyed by the document conveying apparatus to record the image onto the paper, further, it is likely that the recording of image is not smoothly executed as desired, and the recording efficiency decreases. Therefore, it has been desired to improve the document conveying apparatus.
It is an object of the present invention to provide a novel document conveying apparatus which facilitates the manual operation for correctly positioning the leading end of the document to be at right angles with the direction of conveyance and consequently, can reliably prevent the document from being fed aslant to reliably prevent the document from being damaged.
It is another object of the present invention to provide a novel document conveying apparatus which facilitates the manual operation for correctly positioning the leading end of the document to be at right angles with the direction of conveyance even when the document has a large size and consequently, can reliably prevent the document from being fed aslant to reliably prevent the document from being damaged.
It is a further object of the present invention to provide a novel image-forming machine which guarantees the execution of a smooth recording of image as desired with a high image-forming efficiency as a result of the provision of a document conveying apparatus which facilitates the manual operation for correctly positioning the leading end of the document to be at right angles with the direction of conveyance and as a result, can reliably prevent the document from being fed aslant to reliably prevent the document from being damaged.
It is a still further object of the present invention to provide a novel image-forming machine which guarantees the execution of a smooth recording of image as desired with a high image-forming efficiency as a result of the provision of a document conveying apparatus which facilitates the manual operation for correctly positioning the leading end of the document to be at right angles with the direction of conveyance even when the document has a large size and as a result, can reliably prevent the document from being fed aslant to reliably prevent the document from being damaged.
According to one aspect of the present invention, there is provided a document conveying apparatus comprising a document conveying passage and a pair of document introduction rollers disposed at a document insertion portion on said document conveying passage, wherein:
said document conveying apparatus further comprising a support frame body disposed on the upper side of said document conveying passage and a cover frame supported pivotably by said support frame body;
said pair of document introduction rollers are constituted by a driven roller disposed on the lower side of said document conveying passage and a follower roller supported by said cover frame, said cover frame is allowed to turn selectively between a closed position where said follower roller is brought into pressed contact with said driven roller and an open position where said follower roller is located at an upper position away from said driven roller, a shutter member is supported on the downstream side of said pair of document introduction rollers to freely move up and down between a shut-off position where said shutter member shuts off said document conveying passage so that the leading end of a document inserted in said document conveying passage from said document insertion portion comes in contact therewith and is positioned and an open position where said shutter member retracts upward from said document conveying passage to permit the movement of said document, and said cover frame and said shutter member are interlocked to each other so that said shutter member is moved up to said open position when said cover frame is turned to the closed position and that said shutter member is moved down to said shut-off position when said cover frame is turned to the open position.
It is desired that a cam means capable of moving up and down said shutter member is disposed in said cover frame, an elastic member is disposed between said support frame body and said shutter member to urge said shutter member toward the open position and when said cover frame is brought to said open position, said shutter member is brought to the shut-off position by the action of said cam means against the resilient member and when said cover frame is brought to the closed position, said shutter member is brought to the open position by said elastic member as it is no longer acted by said cam means.
It is desired that said cam means is constituted by a leaf spring member having an arcuate cam surface, said shutter member has a to-be-depressed surface formed thereon, when said cover frame is turned to the open position, the cam surface of said leaf spring member is brought to an acting position where it depresses the to-be-depressed surface of said shutter member to move said shutter member down to the shut-off position against the elastic member and, when the cover frame is turned to the closed position, the cam surface of said leaf spring member is brought to a non-acting position where it substantially releases a depressing pressure to the to-be-depressed surface of said shutter member, permitting said shutter member to move up to the open position by said elastic member.
It is desired that said cover frame is rotatably supported by the support frame body via a turn shaft and, when said cover frame is turned to the open position, said leaf spring member brought to the acting position forcibly turns said cover member on the turn shaft to hold it at the open position.
It is desired that said shutter member is supported by said support frame body so as to be moved down to the shut-off position from the open position due to its own weight and to be moved up to the open position from the shut-off position against its own weight, an acting protuberance is disposed on said cover frame to move said shutter member up and down with the turn of said cover frame, a to-be-acted surface is formed on said shutter member, said to-be-acted surface of said shutter member is disposed on a locus of turn of the acting protuberance of said cover frame and when said cover frame is turned to the closed position, said acting protuberance is brought into contact with said to-be-acted surface of said shutter member from the lower side to move said shutter member up to the open position against its own weight and when said cover frame is turned to the open position, said acting protuberance moves in a direction to separate away downwardly from the to-be-acted surface of said shutter member, permitting said shutter member to move down to the shut-off position due to its own weight.
It is further desired that provision is made of an inserted document detector means disposed in the document insertion portion to detect the document that is inserted, an open/close position detector means disposed in the support frame body to detect the open position and the closed position of the cover frame, and a control means which, when the document is inserted in the document insertion portion and the cover frame is brought to the closed position, rotatively drives the pair of document introduction rollers in response to detection signals from said inserted document detector means and said open/close position detector means.
According to another aspect of the invention, there is provided an image-forming machine equipped with a document conveying apparatus of claim 1, for reading the image of a document conveyed by the document conveying apparatus and recording it onto a paper.